1. Field of the Invention
Example embodiments of the invention relate to a solar cell and a method for manufacturing the same.
2. Description of the Related Art
Recently, as existing energy sources such as petroleum and coal are expected to be depleted, interests in renewable energy for replacing the existing energy sources are increasing. As the renewable energy, solar cells for generating electric energy from solar energy have been particularly spotlighted.
A solar cell generally includes a substrate and an emitter layer, which are formed of semiconductors of different conductive types, such as a p-type and an n-type, and electrodes respectively connected to the substrate and the emitter layer. A p-n junction is formed at an interface between the substrate and the emitter layer.
When light is incident on the solar cell having the above-described structure, electrons inside the semiconductors become free electrons (hereinafter referred to as “electrons”) by the photoelectric effect. Further, electrons and holes respectively move to the n-type semiconductor (e.g., the emitter layer) and the p-type semiconductor (e.g., the substrate) based on the principle of the p-n junction. The electrons moving to the emitter layer and the holes moving to the substrate are respectively collected by the electrode connected to the emitter layer and the electrode connected to the substrate.
An interdigitated back contact solar cell capable of increasing the size of a light receiving area by forming both an electron electrode and a hole electrode on a back surface of the substrate, i.e., the surface of the substrate on which light is not incident, has been recently developed. Hence, the efficiency of the interdigitated back contact solar cell is improved.
However, as described above, in the interdigitated back contact solar cell, because the p-n junction and each of the electron electrode and the hole electrode have to be formed on the back surface of the substrate, a patterning process is necessary to separately dope p-type impurities and n-type impurities. Thus, an alignment process for aligning each layer is required to manufacture the interdigitated back contact solar cell. As a result, an alignment mark used to align each layer is positioned on the back surface of the substrate.